Autotractor.



. c. L. BEST AUTOTRAETOR, AP PLIGATION FILED JUNE25, 1912 4 2; I Patented Jan. 13,1914.

INVENTOR.

MAM) ovum/A 0 a 1 If z A TTOR NE Y.

lti

' parts;

CLARENCE L. nnsr, or salt LEannn'o, camronnra.

auro'rnacron.

acetone.

. hpecificationof Letters Patent.

Patented at an. id, thr ll.

Application filed June a, 191a. ssnarnojroa'zaa To all whom it may concern:

Be it known that T, CLARENCE L. BEST,- a resident of the city of San Leandro, county of Alameda, and State of California, have invented new-and useful improvements in Autotractors, of which the following is" a specification.

Th s invention relates to improvements in auto-tractors, and particularly to the steer-f ing mechanism thereof.

. The objectssought to be accomplished are to provide a steering gear, wherein the rotation of the steeringcolumn is transmitted directly to the turntable of the pilot wheel with the minimum number ct interposed and to provide compensation for irregularity or eccentricity of the turntable in revolving about its vertical axis.

Eroadly the invention consists of a turntable comprising an angular concentric ring with an inturned flange and tiiredto' the front of the tractor main frame; and a cora centric angular ring with an outwardly extended flange cooperating with the first m'entioned ring to form an aninilar hall race, with interposed balls therein. The pilot wheel is journaled upon a horizontal axis, mounted within the last named ring. A segment having worm gear teeth in-its periphcry is fixed to the rotatable ring. A worm gear is horizontally pivoted on the fixed rin on the tractor main frame and enmeshed with the segment. The pivotal swing of the worm gear is limited by-adjustabl'e cont-act with a spring fixed on the main frame. The steering column provided with a hand wheel is attached to the worm gear through an intermediary universal joint. 1

In. the drawings, Figure l,is a diagram matic side elevation of a tractor having this invention applied thereto. Fig. 2 is a .frag mentary detail illustrating the application of this invention to-the turntable of a tractor pilot wheel. Fig. 3 is a detail in vertical cross section on the line 2-2 of the same. Fig. 4 is a side elevation of the same.

In detail, the construct-ion consists of the concentric ring 1 having the inturned flange 2 forming a part thereof, the whole being fixed between the side beams :11 of'the tractor main frame, of which it becomes a fixed part and will hereinafter be referred to as the fixed ring. v

The second ring consisting of the concentric ring 3 having the inturned fiange 4 forming a part thereof, will hereinafter be referred to as the rotatable ring. The assemblage of the fixed and the rotatable ring posed ir'ee rolling balls 5 adapted to trans wit the weight on the tractor main frame tothe pilotwheel and reduce the friction incident to steering the latter. These rings are held in proper relation to each other by the interposed balls under normal circumstances, and bythe brackets G fixed to the rotatable rin -and overhanging the flange ot the tired ring. Under certain conditions of travel,- suchas crossing ditches or the like, when the weight might be removed'from the pilot wheel, these brackets prevent it from dropping out of assemblage.

The gear segment 7 has the gear teeth 8 .for-med in its periphery which is concentric with the rotatable ring towhich it is fixed by the brackets 9 bolted to the ring.

The worm gear 10 enmeshed with the segment is journaled in the bracket 11 which is pivoted on the pins 12 fixed in the brackets '13 bolted to the tractor main fr'ame. The

forms an annular ball race for the interswing of the bracket 11, on thepivot 12 is limited by the scroll spring 14 bolted to the main frame, its free end bearing against the headof the bolt 15 threaded into the boss 16 formed on the bracket 11, and is locked by the jam nut 17.

Rotation is transmitted to the shaft 18 of the worm from the steering column 19 through the interposed universal joint 20.

The steering column 19 is provided with the steering wheel 20 located convenient to the operator. Power steering is easily accomplished by interposing suitable gearing. be tween the prime mover and the steering column 19. I

Inasmuch as it is impracticable in this classof machinery to preserve that precise pitch alinement necessary to the proper working of a worm gear, it is therefore as substantial improvement to introduce .a compensating clement where concentric alinement of the turntable is liable to be disturbed by fundamental inaccuracies, subsequent wear or sudden shocks incident to road contact of the pilot wheel. The resilient pressure of the spring 14: preserves absolute engagement of the worm and the segment except in those rare. instances when a sudden twist of the pilot wheel suliicient to wreck the steering gear occurs; in which event the sudden shock would thrust the worm out of engagement against the presshock.

sure of the spring 14, which would immediately return it to engagement after the This construction saves the entire steering mechanism from any strains greater than those equal to the power of the compensating spring.

Among the primary advantages of the direct application of the worm and gear engagement between the pilot wheel and the steering column is the absolute locking of the pilot wheel in the desired position, due to the irreversibility of the action between the driver and 'the driven elements of the worm gear. The secondaryadvantages are the elimination of reducing gears and other complications, the economy inmanufacture due to the lack of necessary precision in construction and assembling, the absence of many wearing parts and their cost of maintenance, etc.

Having thus described this invention, what is claimed and desired to secure by Letters Patent is:

.1. A steering gear for tractors comprising a fixed ring on the main frame, a pilot wheel mounted on a rotatable ring, free rollers interposed between the fixed and rotatable rings, a gear segment fixed on the rotatable ring, a bracket pivoted on the fixed ring, a worm mounted in said bracket and adapted to engage the segment, the axis of said worm being parallel with the pivot on said bracket, and means for rotating said worm gear.

2. A steering gear for tractors comprising a fixed ring, a pilot wheel on a rotatable ring, a segment fixed on the rotatable ring, a bracket, a pivot connecting said bracket with said fixed ring, a worm mounted in said bracket and adapted to engage said segment, the axis of said worm extending parallel with said pivot, a cooperating Y spring mounted on the fixed ring and hearing against said bracket, and means for rotating the worm gear.

3. A steering gear for brackets com rising a fixed ring, a pilot wheel mounte on a rotatable Wheel, free rollers interposed between said rings, a segment fixed to the rotatable ring, a bracket, a pivot connecting said bracket with said fixed ring, a worm mounted in said bracket and held in. resilient engagement with said segment, the

axis of said worm extending parallel to said worm gear.

5. A steering gear for tractors comprising a pilot wheel mounted on a ring rotatable in the tractor frame; a segment fixed on the rotatable ring, a Worm gear mounted in a bracket pivoted on the tractor frame, a

spring fixed to the' tractor frame and bearing against the mounting of the worm gear, and means for regulating the tension of said sp ring.

6. A' steering gear for tractors comprising a pilot wheel mounted on a ring rotatable in the tractor frame, a segment fixed on the rotatable ring, a bracket, a pivot connecting said bracket with the tractor frame,

a worm mounted in said bracket, the axis of said worm being parallel with the pivot of said bracket, means for yieldingly holding said worm in meshwith said segment, and means for regulating pressure of said holding means.

'7. A steering gear for tractors comprising a pilot wheel mounted on a ring rotatable in the tractor frame, a segment fixed on the rotatable ring, .a bracket, a pivot connecting said bracket with the tractor frame, a Worm mounted in said bracket, the axis of said worm being parallel with the pivot of said bracket, means for yieldingly, holding said worm in mesh with said segment, means for regulating pressure of said holding means, .a spring mounted on the fixed ring and bearing against the top of said bracket, and means for rotating said worm.

CLARENCE L. BEST. \Vitnesses:

BALDWIN VALE, Enw. F. SULLIVAN. 

